This invention relates to an improved method and apparatus for metering active electrical energy by solid state electronic techniques and in particular, relates to an improved meter having internal error correction and power supply means for the active components of the meter.
Electrical energy (kWh) has been and continues to be metered with the familiar rotating disc-type of meter. In addition, the instrumentation and metering arts include proposed systems having apparatus employing electronic and solid state devices for measuring power and energy. In such apparatus, the electronic and solid state devices replace the conventional rotating disc.
Further, there have been disclosed metering systems for metering electrical energy in an electrical system which involves producing analog signals from line currents and voltages. Pairs of analog signals representing current and voltage variables are processed in time division multiplier networks which multiply the analog signals to provide a series of width and amplitude modulated pulse signals each representing instantaneous partial power. Pulse signals from different multiplier networks are summed to provide another series of pulse signals each representing instantaneous total power. The series of pulse signals representing instantaneous total power are processed through a low pass filter to provide another signal representative of average total power in the system. Subsequently, the signal representing average total power is processed in an analog-to-pulse rate converter which produces a series of output pulse signals each representing a quantized amount of electrical energy. A stepping switch and register perform conventional accumulation, storage and display functions in response to the series of output pulse signals delivered thereto. None of these systems includes a method and apparatus for providing, in combination, a source of internal power for driving the active circuit components of the metering system, while at the same time providing internal error correction, and none of these systems discloses or suggests a means wherein an internal power supply provides sufficient energy for efficiently and effectively driving a mechanical display means.
It therefore it an object of this invention to provide an improved method and apparatus for metering kWh in a solid state electronic metering system wherein the metering system has an internal power supply with internal error correction.
It is another object of this invention to provide an improved method and apparatus for metering electrical energy wherein the metering system has an internal power supply with internal error correction wherein the power supply provides energy sufficient for driving a mechanical energy display means.